Dynamo-electric machine.



V. A. FYNN.

DYNAMO ELECTRIC MACHINE. APPLICATION FILED MAR. 16. 1914.

1 1 8 3,000 Patented May 16, 1916.

- lar conditions.

UNITED STATES PATENT oFFIcF.

VALFRE ALFRED FYNN, O ST. Louis, MISSOURI, ASSIGNOR TO WAGNER pEc'rRIcMANUFACTURING COMPANY, OF ST. LOUIS, MISSQURI, A CORPORATION OF MIS-SOURI.

DYNAMIC-ELECTRIC MACHINE.

Specification of Letters Patent.

Application filed March 16, 1914. Serial No. 824,878.

'have invented a certain new and useful Dynamo-Electric Machine, ofwhich the following is such a full, clear, and exact description as willenableany one skilled in the art to which it appertalns to make and usethe same, reference being had to the accompanying drawings, forming partof thls specification.

My invention relates particularly to a d1- rect-current generatoradapted to give a practically constant ou tput 1rrespect1ve of the speedat which 1t 1s driven. I

It is known that the output of a directcurrent generator can be limitedby connecting the exciting wlnding between a main brush and an auxiliarybrush located somewhere between the two main brushes, but such anarrangement merely limits the output of the generator and does not keepthe latter anywhere near. constant, the current rising very rapidly atfirst, reachmg a then quickly diminishing with a further increase inspeed.

It is the object of my invention to provide a generator in which theoutput will remain practically constant for all speeds, and in which theshape of the output curve can be readily adjusted to suit the particu- II achieve this object by using two exciting windings, connecting the onebetween'a main brush and an auxiliarv brush on one side thereof, and theother between the same main brush and another auxiliary brush located onthe other side of the said main brush. give to the one winding moreturns and a higher resistance than to the other, and to secure thedesired output curve shape by adjusting the position of one excitingbrush, or of both.

The accompanying drawing diagrammatically represents a two-pole machineembodying my invention. Referring to the drawing, 2 represents acommuted winding on the armature, with which cooperate main brushes 3,4, preferably located in the neutral zone, and tWo auxiliary brushes 5,6, located under poles of opposite polarity and somewhere between themain brushes. These brushes are, as is now usual, shown I prefer to asrestingon the commuted winding itself. This conventional showing makes.all ref erence to connections between the commuted winding and thecommutator unnecessary, for reference to brush position locates thearmature conductors which are first reached from each brush.

7 is a low resistance shunt exciting winding of a few turns connectedbetween the main brush 4: and the auxiliary brush 5, and 8 is a highresistance shunt exciting winding of many turns connected between themain brush 4 and the auxiliary brush 6. The dynamo is adapted to'cooperate with the storage battery 14 so as to charge same, and may alsobe used to help said storage battery to supply the translating devices15, 16, included in consumption circuits controlled by the switches 17and 18.

An automatic battery switch of known construction is interposed betweenone pole of the storage battery and the main brush 3. This automaticswitch comprises a movable member pivoted at 12 carrying at one end acontact 21 adapted to cooperate with the stationary contact 13 and atthe other an armaturell adapted to cooperate with the magnet 22. Thespring 23 normally holds the contacts, 21 and '13 apart. The magnet 22carries a shunt winding 10 connected across the main brushes 3, 4, and aseries winding 9 included between the contact 21 and the main brush 3.

The mode of operation is somewhat as follows: As soon as the dynamo haspicked up any increase in speed will very rapidly increase both excitingvoltages and also the voltage at the main brushes, thus increasing themagnetizing effect of coil 10 of the automatic switch. Vhen the dynamovoltage reaches a value approximately equal to the mean terminal voltageof the storage battery 14, then the armature ll of the au-.

tomatic switch will be attracted and the circuit between the dynamoand'the storage battery will be closed at the points 18 and 21. Anyfurther increase in speed will cause the dynamo to send a chargingcurrent into the storage battery, which charging current will increasethe magnetization of the automatic switch, because it circulates throughthe coil 9 thereof, so as to produce a magnetization of same directionas that due to the coil 10. The terminal voltage will vary somewhat withthe condition of charge of the storage battery, as is now wellunderstood, rising a, little with increasing battery charge, but thevoltage between the main brush 4: and the auxillary brush 5, also thatbetween the mam brush 4: and the auxiliary brush 6, will varyconsiderably with the speed and the load. The proportions are so chosenthat the excitation due to the winding 7 is, at first, considerablygreater than that due to 8. For the direction of rotation and thedirection of the magnetic fiux produced by the field windings indicatedin the figure,the voltage between the brushes 4: and 5 will diminish andthat between 4: and 6 will increase with increasing speed or.wi hincreasing load. Under these circumstances, the proportion of the totalmagnetization supplied by the winding 7 will be great at low speeds andsmall at the higher speeds, while the reverse will be true of themagnetization due to the winding 8, with the result that the currentoutput of the generator, which tor a given speed and given externalconditions, depends on the total magnetization of the machine, will notdroop as fast with increasing speed as it would do if the shunt winding7 were alone present. By movlng the auxiliary brush 5 with relation tothe main brush 4:, I can adjust the regulation due to the droopingexcitation produced by the field winding 7, and, by adjusting theauxiliary brush (3 with respect to the main brush 4;, I canindependently adjust the rising excitation due to the exciting winding8. The fact that I am able to adjust these two megnetizationsindependently of each other, not only enables me to secure a prac--tically constant current output irrespective of speed, but also makes itpossible to vary.

the output curve within very wide limits and to adjust it in almost anydesired manner much more readily and accurately than would otherwise bepossible.

The translating devices 15, 16, may be operated either from the batteryor from the battery and the dynamo.

Having fully described my invention, what I claim as new and desire tosecure by Letters-Patent of the United States is:

machine,the comprovided with a 1. In a dynamo electric bination with anarmature commuted winding and maln and auxiliary same main brush as thefirst and to another auxiliary brush, at least one of said auxiliarybrushes being located within the influence of the field magnetization.

2. In a dynamo electric machine,the com bination with an armatureprovided with a commuted winding and main and auxiliary brushes, of twofield windings each displaced ninety electrical degrees with relation tothe main brushes, one of said field windings being connected to a mainbrush and to an auxiliary brush, and thesecond field winding beingconnected to the same main brush as the first and to another auxiliarybrush.

3. In a dynamo electric machine, an armature having a commuted winding,main and auxiliary brushes cooperating therewith, a field windingconnected to a main and to an auxiliary brush, and a second fieldwinding othigher resistance and more turns than the first connected tothe same main brush and to another auxiliary brush, said auxiliarybrushes being located within the influence of the field magnetization.

4:. In a dynamo electric machine,the combination with two co-axial fieldwindings, of an armature provided with two main brushes and twoauxiliary brushes, said auxiliary brushes being located under oppositepoles, one of the field windings being connected to a main brush and toan auxiliary brush, and the other field winding being connected to thesame main brush as the first and to the other auxiliary brush.

In testimony whereof, I have hereunto set my hand and atfixed my seal inthe pres ence of the two subscribing witnesses.

VALERIE A. FYNN. [1 s] Witnesses W. A. ALEXANDER, G. M. Snonn.

